Description: Related in size to the black ‘pimple lichens’ (Arthopyrenia) of twigs and bark, this species has similar discs (perithecia) spread over an orange-brown thallus and scratches orange with a fingernail. It is a shy species of smooth-barked trees often growing in shady situations. The species should be searched for between the ’scripture lichens’ especially on ash and sycamore at the shaded base of the main stems or trunk. A squash of the disc viewed under a microscope will show the thrice-divided (three-septate) spores.

Key Identification Features:

• Yellowy-brown thallus, scratching orange with a fingernail, shiny rounded discs (like pimples) and shade habitat, should distinguish it
• Many similar species are more likely to be found on twigs.

Original text submitted by Simon Davey

Distribution Map from NBN: Porina aenea at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Porina aenea at iNaturalist World Species Observations database.